Etjrnace



Feb. 1,1927. 1 1,6163196 A. F. NELSON FURNACE Filed July 21; 1926 2 Sheets-Sheet 1 findrew'Friszoe Nelson Feb. 1,1927.

A. F. NELSON FURNACE Filed July 21, 1926 2 Sheets- Sheet \IIIII flndrew Frzlsioe Nelson My K W flctom Patented Feb. 1, 1927.

UNITED STATES PATENT OFFICE.

ANDREW FRISTOE NELSON, 0F SEATTLE, WASHINGTON.

FURNACE.

Application filed. July 21,

My invention relates to an improvement in furnaces, and particularly in furnaces designed for the use of soft coal. As shown herein, the invention is applied to an electrically welded one piece furnace, but the principles thereof may be applied with equal facility to all types of furnaces, including cast furnaces.

Present day designs of furnaces are adaptations of furnaces originally designed for burning hard coal, which has but little volatile matter. They are designed to obtain a good draft so as to supply oxygen to the coal upon the grate, and to obtain sufficient contact of fresh air with the radiator as the air circulates through the furnace casing, but little attention has been paid to the efficiency of such furnaces when burning soft coal. To obtain efficiency with such coal, it is necessary not only to have an adequate draft but to apply the oxygen in such a manner that the volatiles distilled from the coal are consumed before they pass out with the draft and up the chimney beyond the point where the heat of their combustion can be transferred to the radiator of the furnace.

My invention is designed therefore, as a means whereby the volatiles and likecombustible products of soft coal can be completely consumed, and can be consumed at a point where they will be most elfectivein transmitting heat to the circulating air surrounding the furnace body, in this manner increasing the efficiency of the furnace.

My invention comprises the novel parts and the novel arrangement thereof as shown in the accompanying drawings, described in the specification, and particularly defined by the claim terminating the same.

In the accompanying drawings I have shown my invention in a form which is now preferred by me.

Figure 1 is a general perspective view of the furnace body, with parts broken away, illustrating my invention associated with an electrically welded one piece furnace.

Figure 2 is a section substantially on the line 2 2 of Figure 1 through the radiator of such a furnace.

Figure 3 is a vertical section through the radiator and upper part of such a furnace on the plane of the smoke pipe.

As shown in Figure 1, such furnace comprises the body portion 1, having a pouch at its front, this pouch having the usual 1926'. Serial No. 123,876.

feed door 11, the draft door 12, and the ashpit door 13. Preferably the said door 11, which is above the normal level of coals upon the gratelst, is provided with a secondary draft opening and damper illustrated at 15.

The upper portion of the body 1, above the grate let, forms a primary combustion chamber designated in general by the numeral 16. This leads into a radiator 2, and preferably the entrance into the radiator 2 is restricted, this entrance'beingjoined to the upper portion of the furnace body 1, in the forms shown, by means of a cone 17. The entrance 20 to the radiator 2 is cut ofi from direct communication with the outlet to the smoke pipe 3 by means of a baffle 21. This may be doubled as shown herein, and with the upper and lower plates 22 and 23 respectively of the radiator perforated, a crescent shaped aperture 24: is left through the radiator for circulation of air. Through the provision of the baflle, a large chamber is left in the forward portion of the radiator, which receives the gases from the primary combustion chamber 16. To reach the smoke pipe 3, these gases must pass around the ends of the ball'ie 21 and then must be drawn downward, for it will be seen that the outlet 30 from the radiator is well below the upper plate 23 of the radiator.

There is thus provided an area at the top of the radiator and below the level of the outlet 30, wherein may gather the unconsumed products of combustion. Passing tl'irough the restricted inlet 20 into the comparatively free and open radiator 2, and into the large chamber formed therein forward of the baffle 21, these gases will tend to remain in the radiator and will not pass out directly to the restricted outlet 30. This gives a chance for additional air, entering at 15 above the grate, to mix with these combustible products of distillation, and through heat transmitted thereto from the combustion chamber 16, these will ultimately be consumed. I

There is thus provided a secondary com bustion chamber 26 in the upper part of the radiator, as indicated by the dotted line A in Figure 3. As these gases are consumed they will naturally expand and they will, of course, be drawn out by the draft through the smoke pipe 3, but by reason of the location of the outlet 30 below the top of the radiator, this withdrawal ofthese gases will be sufficiently slow to permit practically complete combustion thereof. This secondary combustion chamber 26 being located at the top of the radiator, the secondary combustion within the radiator will affect the upwardly moving circulating air, and Will impart to it a final intense heating effect just as it passes upward into the air pipes, or out to the register in the case of a pine-less furnace.

The effect described is attained through two principal agencies; one, the provision of a chamber of comparatively large capacity, as compared with the restricted inlet and out-let openings, and separated by a baffle from the outlet opening, whereby the draf induced movement of the gases retarded to give the gases a chance to burn completely; and another, the location of the smoke-pipe connection well below the upper plate of the radiator, so that the hot gases will tend to remain inthis upper, dead space, irrespective of the battle. The us of such a baffle, or the location of the smoke pipe thus, might alone be suflicient, but in combination they effect practically complete combustion of all combustibles in the soft coal, and markedly increase the efliciency of the furnace.

What I claim as my invention is:

In a furnace, a radiator having a lower plate apertured substantially centrally to form an inlet, a flat upper plate, a peripheral plate joining'the edges of the upper and lower plates, and itself apertured at its rear side, well below the upper plate, to form a smoke outlet, and a substantially crescentshaped baifle positioned between the inlet and outlet, and joining the upper and lower plates, inward of the peripheral plate, and having its ends diverging forwardly, and outwardly from said inlet, to define an expansion chamber extending over the entire area of said radiator forward of the batlie, and including that part of the radiator which lies above the level of the top of the outlet, said bafile being spaced from the pe ripheral plate and cooperating therewith to form smoke passages connecting said chamber and the inlet with the outlet.

Signed at Seattle, King County, Washington, this 28th day of June, 1926.

ANDREW FRISTOE NELSON. 

